This invention relates to anti-inflammatory agents and methods of preparing and using anti-inflammatory preparations.
Anti-inflammatory and analgesic agents have been topically applied. In one prior art example (European Patent Application, EP0087062B1, 09, 02, 83), the preparation and use of an emulsion cream containing a maximum of 5 percent ibuprofen in its racemic form is described. The patent application claims that since ibuprofen is a highly lipophilic drug and has a very poor aqueous solubility, it was not possible to disperse ibuprofen in an aqueous phase to make a suitable cream. Accordingly, the ibuprofen cream was prepared by dissolving it in the lipid phase using the oily components of the formula and then emulsifying the same as an o/w emulsion cream. However, it is known that a lipophilic drug dissolved in a lipid phase of the emulsion system has poor release properties and hence will show a very poor cutaneous absorption at the site of application. Surprisingly, it was found that ibuprofen in its racemic form as well as in its enantiomeric S-form, both of which have very lipophilic properties, can be easily dissolved in very high concentrations in certain hydrophilic solvents. These hydrophilic solvents such as PEG-7-glycerylcocoate or PEG-200 monolaurate are miscible with both aqueous or hydrophilic as well as the lipid components and thus do not suffer from the disadvantage of the poor release properties associated with the emulsion systems where lipophilic drugs are dissolved in lipids. Additionally, these solvents act as very good cutaneous absorption promoters in the intact skin. The skin penetration properties are further enhanced when combined with hydrophilic excipients such as propylene glycol. Hence, the objective of the present invention was to develop a high concentration ibuprofen containing emulsion cream that contains ibuprofen or its S-enantimoer dissolved in the hydrophilic phase of the emulsion cream that also enhances skin penetrability.